Method of and apparatus for testing loose geological formations



Feb. 22, 1944. c. s. COOLEY 2,342,253

METHOD OF AND APPARATUS FOR TESTING LOOSE GEOLOGICAL FORMATIONS FiledDec. 16, 1959 zz J7 0 I I 27 JI IN VENTOR.

ATTORNEYE.

Patented Feb. 22, 1944 UNITED STATE METHOD OI AND APPARATUS FOR TESTINGLOOSE GEOLOGICAL FORMATIONS Cecil G. Cooley, Chillicothe, Mo.Application December 18, 193,, Serial No. 309,541.

. 9 Claims. ('01. 255-14) This'application is a continuation in part of,and a substitute for, my co-pending application Serial No. 114,818,filed December 8, 1936.

In the testing of sand and gravel deposits, or other loose geologicalformations-, two methods are in common use. Inone, an open well is duginto the deposit to be tested, this method having the disadvantages thatpiling is necessary it cavingoccurs and that water, if encountered, mustbe removed. In the other method, a pipe sim; ilar to a well casing isdriven into the ground and the materials which come up inside the pipeare periodically bailed out. When the pipe encounters a boulder or otherobstruction; it is necessary to interrupt the sampling process and thesinking of the pipe and to break up the boulder by a suitable toolinserted through the pipe.

It is the object of my invention to produce a process and apparatus forsampling gravel, sand,

or other loose geological formations and to do so infa manner which willbe free from the objec- "tions inherent in the prior. sampling methodsmentioned above. More specifically, it is my object to obtain by anuninterrupted process a continuous sample of loose material in'the formv the medium of a connecting rod l2 and crank I3.

rel (desirably having an internal diameter of at well-drilling rig, Irotate the core-barrel, preferably in timed relation to the frequency ofthe strokes of the drill rig at a rate which will move thecore-barrelthrough an angle equal to half that between adlacent cutting teeth foreach 1 tend to prevent-the material within it from escaping when thecore-barrel is raised.

The core-barrel is driven into the deposit being tested in the manneroutlined above. When. the cutting element has reached the bottom of theformation to be tested, andnot before, the corebarrel is drawn from theground. During the withdrawal operation the pipe or core-barrel isslowly rotated to reduce static friction and ob viate the necessity ofjarring the core-barrel and thus disarranging the loose materialconstituting the core. The material within the core-barrel is elevatedwith it and represents an accurate cross section of the deposit throughwhich the core-barrel is driven.

The accompanying drawing illustrates my invention: Fig. 1 is a sideelevation of a well-drilling rig embodying my invention; Fig. 2 is avertical section on an enlarged scale through the core-barrel and themeans employed to rotate it; Fig. 3 is atop plan view .01 thebarrel-rotating mechanism; and Fig. 4 is a view similar to Fig. 2, butillustrating the upper end of the core-barrel as ready to be drawn fromthe ground.

The well-drilling rig employed in practicing my invention may takedifierent forms, and that illustrated in the drawing anddescribed hereinis to be understood as merelyone example. The rig shown is portable innature, being mounted on, an automotive truck Hi. In common with mostdrilling rigs, it embodies a pivoted beam' I I which is oscillated in avertical plane through The beam it carries two sheaves l4 and I5,mounted respectively near the outer and inner ends of the beam. A cablel8, having one end secured to a winding drum l9, passes therefromsuccessively around the sheaves l5 and H and thence arounda sheave 20 atthe top of a mast 21. During the process of driving the pipe, the freeend of the cable l8 isattached to a driving rod 22 carrying a weight 23.It will be evident from this description that as the crank [3 isrotatedthe driving rod 22- and its associated weight 23 will bealternately raised and lowered.

A suitable-source of power, such asan internal combustion engine 25, ismounted on the truck III to drive the crank 13 and other moving parts orthe apparatus.

Mounted in rearof the mast 2|, I provide a rotating table 21conveniently supported from a suitable base 28 through an anti-frictionbearing relative to the core-barrel. I also prefer to provide thecore-barrel with some means which will.

29. The table 21 has an axial hole or opening clamp 3|, to the drillpipe or core-barrel 321.

I internal diameter or the core-barrel.

sleeve is free to slide vertically in the table 21, but the presence ofthe splines in the sleeve and the keyways in the table compels thesleeve, and

- the core-barrel 32, to rotate with the table.

presented cutting edges. At the: upper end of.

the shoe, its internal and external diameters correspond respectively tothose ofthe core-barrel 32. At the lower end of the shoe, however, thebore is made slightly smaller than the internal diameter or thecore-barrel, and from its lower end the bore flares upwardly graduallyto the This insures that any object small enough to enter the lower endof the sleeve will not become wedged in the core-barrel and tends toprevent such material from dropping from the core-barrel when it iswithdrawn. Moreover, because of the disarrangement incident to thecutting action, the material constituting the core will not infrequentlypossess a higher proportion of voids than it did in its original stateand will thus ordinarily occupy a greater volume; and by constricting sg tly the boreof the shoe at the lower end thereof, the amount ofmaterial entering the core-barrel is reduced and the core thus preventedi'rom attaining a length materially greater than the depth to which thedrill is sunk.

The core-barrel 32 is preferably made up of sections interconnected byscrew-thread joints which are flush on both the inner and outersurfacesof the barrel, and the shoe 35 is connected to the lowermost of suchsections through a similar joint. I have found it convenient to make thesections or the core-barrel 32 about eight inches in externaldiameten-about seven inches in internal diameter, and about six feet inlength. At the lowerendof the shoe the diameter of the bore thereof maybe in the neighborhood of six and one-half inches-or about 7% less thanthe internal diameter or the core-barrel.

The diameter of the core-barrel is of considerable importance forseveral reasons. There is always a possibility that the shoe willencounter squarely a rock or boulder which is slightly larger indiameter than the bore of the shoe and which might become wedged thereinto be driven downwardly into the deposit ahead of the shoe, thusinterfering with the cutting action, preventing material from enteringthe core barrel, and causing an inaccurate sample to be obtained. As thediameter or the core-barrel and of the shoebore is increased, thechances of the shoe engaga boulder of a size tobecome wedged :in theshoe-bore are correspondingly decreased; and

moreover, the larger the boulder wedged in the shoe-bore the greaterwill be the resistance it 'the core-barrel the greater its strength inpro- Portion to the i'orceawhich are imposed upon it in operation. Inview of these considerations, 1

The-

prefer to employ a core-barrel of not less than live inches internaldiameter.

For reasons set forth above, the internal di-' ameter of the shoe at itslower end is made slightli 1y smaller than the internal diameter of thecorebarrel itself. In practice, it is found expedient to make the boreof the shoe at the-lower end thereof about to 10% less than the internaldiameter or thecore-barrel. If the shoe-bore is materially larger thanthis, inadequate assurance against jamming of large particles within thecore-barrel is provided and the core may tend to climb or to grow longerthan the depth to which the core barrel is sunk; and if the shoe-bore isis made materially smaller than that indicated as expedient, resistanceto progress of the drill is increased and the entrance of material intothe core-barrel is restricted to such an extent that ple is to be taken.The shoe 35 and at least one section of the pipe or core-barrel 32 areconnected together and inserted into the sleeve 3! which is then clampedto the pipe. To prevent injury to the threads at the upper end of thepipe, it is desirable to provide a suitable driving cap such as thatindicated at 40 in Fig. 2. The driving rod 22 is then inserted into thecap and the upper'end of the pipe, and the drill rig is started, thewinding drum IQ being so adjusted that the weight 23 will strike thedriving cap 40 at the lower end oi. each stroke. The table 21 isoperativeiy connected to the engine 25 to be rotated slowly as the pipeis driven, the table conveniently being formed with an annular series ofbevel-gear teeth 42 meshing with a bevel-pinion 43 operativelyconnected, preferably through a change-speed transmission 44 and a rigwhich is rotated, like the crank 13, by power from the engine 25. L

As the drill rig operates, the pipe 32 is driven into the ground, whilerotating slowly about its own axis as a result or the rotation of thetable 21.. Ordinarily the table 21 rotates the Pipe 32 through .an angleequal to about half that between two' adjacent teeth 35 for each strokeof the driving rod 22; altho h, rotation at a ani'erent relative speedmay sometimes be advisable. As the driving 0! the pipe 32 progresses,additional sections are added to it, the sleeve 3| being transferred toeach new section as it is added.

When the pipe has entered the formation to the depth to be tested, theclamp 3| is loosened and the driving rod 22 and driving cap ll removed.Some means, such as the lifting cap I illustrated in Fig. 4, is attachedto the upper end or the drill pipe, and an eye it in the cap is con-.nectedto about on the end or a lifting cable It which extends over asuitable sheave at the top oithemsstfl and-thencetoawindingdrumorWindlass-55. ZBy rotation 01' the winding drum 5!, the pipe 32 iswithdrawn from the ground.

bringing with it all material which entered it as it was driven.Withdrawal of the pipe is facilitated if it is rotated or oscillated asit is elevated. To prevent the loss from the lower end or thecore-barrel of material which has entered thereinto during the drivingoperation, I may provide some means tending to retain such material. asillustrated in the drawing, this means takes the form of an annularseries of light leaf-springs Cl 7 secured at their lower ends to theinner surface drive chain 45, to some suitable shaft of the drill of theshoe3 5. upp r or free ends of the from below, as they are easilydeflected outwardly against the inner surface of the shoe; but when thepipe is lifted some of any material tending to drop from the shoe willbecome wedged be- .tween the outer surface of the strips 50 and theloose material, partly because of excessive friction, partly because thecontinuous rotation disturbs the material and results indisplacementswhich prevent the obtaining of an accurate sample, andpartly because the loose material fills the spaces between the cuttingteeth and interferes with their cutting action. My invention has anadvantage over the process of inter-- mittent pipe-driving and bailingin that the sample obtained. is a continuous one for the entire depthand in that the cutting teeth will cut through any large bouldersencountered.

I am also aware thatit has been proposed to employ core-drills, drivenby combined percus-- sion and rotation, in producing generallyhorispring strips 60 are bent inwardly of the shoe,

as is clear from Fig.2. The strips 60 afford no material resistance tomaterial entering the shoe zontal holes in solid rock. It is to benoted,

however, that the use of core drills in loose formations of gravel orsimilar material such as I contemplate, is materially different from theuse of core drills in solid rock. For example, in solid rock thedrill-shoe cuts clearance for the core-barrel and there is no problem offriction between the core barrel and the material which the drill ispenetrating; whereas in loose formations-the material closes in behindhole as desired; whereas such operation is impossible in the drilling ofloose material. Moreover, a solid-rock core consists of a single pieceor of a comparativelysmall .number of pieces fitting rather closelywithin the core-barrel, and disarrangement of the core is thereforeimpossible; whereas to obtain an" accurate sample of a loose gravelformation, such as my inventionv keep a running record of the level ofthe top of the core as the pipe is'driven. This may be done byinterrupting the drilling operation at regular intervals-say intervalsof one foot in the descent of the pipe, and noting the height of beprovided witha stroke-counter (not shown) and a record kept of thenumber of strokes required to drive the pipe through each foot of itsformation during the drilling operation as to the character of thedeposit being sampled but will also provide a basis for the eliminationof errors which otherwise might arise as the result of verticaldisplacements of the core during the drilling operation. I

Core displacements which might result in error in interpreting thesample can arise from several causes. If the drill is cutting through astratum of loose gravel having a substantial percentage of voids, someof the gravel in the path of the drill may be displaced laterally andnot enter the drill with the result that the whole core will drop. 0nthe-other hand, if the drill cuts through a boulder or stratum of solidrock the action'of the teeth 35 in disintegrating the formation willresult in the. creation of voids which will cause the .core to be forcedupwardly. After the pipe has been driven and withdrawn from the ground,the several pipe sections are removed and the contents of each examinedeither as .an entirety or in increments. The

running record of the height of the top of the core during thedrillingoperation permits the depth of each core-increment to be accuratelydetermined.

At least to some extent, the displacement of the core relative to thesurrounding earth can be reduced by varying the relation between thefrequency of the strokes of the drill rig and the speed of rotation ofthe table 21. Reducing the relative speed of the table tends to lowerthe core, while increasing it tends to raise the core. In takingadvantage of this, I make a continuous observation of the height of thetop of the core, as by means of a flexibletape-line provided at itslower end with a small weight 66 adapted to rest on top of the core. Thedriving cap 40 may have anv opening 61 in its wall .for the passage ofthe tape-line.

If, by reading the tape-line 6Q, it is found that l the core is risingrelative to the surrounding .earth, the variable-"speed transmission 44may be 0 adjusted to reduce the speed of the table. On the other hand,if the core is found to be dropping, the transmission 44 may be adjustedto increase the speed of the table.

I claim as myinvention 1. A machine of the type described, comprising acore barrel, 9. cutting element attached to the lower end of said corebarrel and having an annular series of cutting teeth, mechanism forimparting blows to the upper end of said core barrel to drive it intothe ground, and means 10i rotating said core barrel and operating saidmechanism in timed'relation. said means being adjustable to vary thespeed of pipe-rotation relative, to the speed of said blow-impartingmechanism.

-2. A process of sampling deposits of sand,

gravel, or other loose material which comprises driving a core barrelthereinto by intermittent blows, rotating the core barrel as it isdriven,

0 varying the relative speed or core-barrel rotation the top of the corewithin the barrel, and with drawing the core barrel and the core itcontains.

5 driving a core barrel approximately vertically the top of the core. Ifdesired, the drill-rig may descent. Such a record "will not only giveini to maintain approximately constant the level of.

thereinto by intermittent blows. rotating the core barrelasitisdriven.periodicallymeasuringthe height oi'the top oi the core of loosematerialwithin the barrel, and tly withdrawingthecorebarrelandthelooumaterialitcmv' tains.

4.-A process of sampling deposits ot'sand.

ravel. or other loose material which comprises driving apipe forming acorebarrel approximately vertically thereinto', by intermittentdownwardly directedbiows, rotating the core barrel as it is driven,continuing the blowsand rotation.

untllthedesireddepthtobetestedisattained. anchoring the core of loosematerial 4 against downward movement relative to the core barrel,removingthecorebarrelandcoreiromthe ground by a vertical movement, andsupporting the surrounding loose material upon the exterior surface ofthe core barrel during the driving and removal of the core barrel.

5. A process of sampling deposits of sand.

the-ground tested by subjecting'it simultane ously to an upward pull andto a movement of rotation about its axis, and supporting the surroundinghose material upon the exterior surface of the core barrel during thedriving and removal oi the core barrel.

6. A process of sampling deposits of sand, grave], or other loosematerial which comprises cussion an. elongated tubular core-barrelhaving an open lower endtoseparateirom theremainder 0! the loose deposita cylindrical core, continuing the driving of the core-barrel whilesupporting the surrounding loose material thereby until the desireddepth to be tested is attained. whereby to obtain within thecore-barrels. core which corresponds in length substantially to thedepth of the deposit to be sampled and the geological formation or whichcorresponds substantiallyinpositionandarrangement withthatoi suchdeposit, anchoring such core against downward movement relative to thecore-barrel, and then simultaneously withdrawing the core-barrel and thecore it contains by subjecting the corebarrel'to upward pull whilerotating it about its axis.

8. -A process of sampling deposits of sand, gravel, or other loosematerial. comprising driving into the deposit by combined rotation andpercussion an elongated tubular core-barrel. havins an open lower end toseparate from the remainder or the loose deposit a cylindrical core,

. conflnuing the driving of the core-barrel while driving a' core barrelhaving an inside diameter a of at least five inches into the material ina substantially vertical direction. by vsubjecting it to v rotation andto intermittent downwardly directed blows until the desired depth isattained, where-' bytheinside oi thecorebarrelwillbefllledwith' a, corewhose geological formation will correspondsubstantially in position andarrangement with that of the deposit tested. anchoring the core againstdownward movement in the core,

barrel, withdrawing the core barrel and its contained core, andsupporting the surrounding loose material upon the exterior surface .0!the .core barrel during the driving and removal of the core barrel;

supporting the surrounding loose material thereby until the desireddepth to be tested is attained, whereby to obtain within the core-barrela core which corresponds in length substantially to the depth of thedeposit to be sampled and the geological formation of which correspondssubstantially in position and arrangement with thatof such deposit,anchoring such core against downward movement relative to thecore-barrel. and then simultaneously withdrawing the corebarrel and thecure it contains.

9. A process of sampling deposits of sand, ravel, or other loosematerial, comprising presenting to an exposed faceot such deposit thetoothed end of a coreebarrel having an internal diameter materiallygreater than the diameter of the particles oi whichsuch deposit isformed. rotating the core-barrel while subjecting it to percussion todisplace laterally particles in contact with the toothed end of saidcore-barrel without substantial disintegration of said par- 7. A processof sampling deposits or sand,

gravel, or other loose materiahcomprising driving into the deposit bycombined rotation and pore moval of the core barrel.

ticles, continuing such rotation and percussion to drive the core-barrelinto. the deposit to the depth to be tested, anchoring loose materialwithin the core-barrel against relative downward displacement,simultaneously withdrawing the core-' barrel and all the loose materialwhich entered its lower end as it was driven, and supporting thesurrounding loose material upon the exterior sur-' face oi the corebarrel during the driving and reo. COOLEY.

